Laminated glass



. J. C. BRIER ET AL LAMINATED GLASS Filed July 18. 1927 gmm'nto John C. Brier 70 George 5. W61 f/(rns lL/l/buf F BI Q-Q/n atkoumq Patented Aug. 23.

UNITED STATES PATENT-ouncev.

JOHN G. BBIER AND GEORGE .B. WATKINS, or ANN nson, moment, AND WILBUR r. ,nnown, or renew, om nssrenons 'ro LIBBEmownns-ronn GLASS compan F TOLEDO, OHIO, A CORPORATiON OF OHIO LAMINATED GLASS Application filed m 18, 1927. Serial No. 206,416.

A further object of the invention is to pro- I vide a laminated glass product comprising a plurality of sheets of glass and an intermedis ate layer of plastic material, the intermediate layer being of such a nature that it can be united to the remaining laminations with-- out the necessity and expense of curing the same, the said plastic materi'alincluding ingredients that will give a resultant'mass hav-' ing a low vapor pressure.

Still another object of the invention isto provide a plastic particularly well adapted for use in the manufacture of laminated glass, said plastic being a mixture of plas ticizers and solvents of such a character. that the resulting vapor pressure of the mixture is reduced, by mutual solution, to a relatively very low point.

Other objects and advantages of the inven tion will become more apparent during the course of the following description.

In the drawing wherein-like numerals are employed to designate like parts throughout the same,

Fig. .1 is a diagrammatic View illustrating the formation of a plastic material.

Fig. 2 is a diagrammatic sectional view illustrating the laminations before they have been united,

Fig. 3 represents diagrammatically a press that may be used to accomplish the uniting of the laminations,

Fig. 4 is a fragmentary sectional view showing the laminations after they have been united, and

Fig. 5 is a modified form of product formed in accordance with the same process.

Heretofore, in the production of laminated" glass, ithasbeen customary to'use acellulose sheet-material as the plastic part of the sandwich; andwhile thus far no process has been developed which does not at times experience let-goes, it hasbeen found in practice that thech'ances of having let-goes are greatly reduced by using seasoned 'or cured cellulose materiah The necessity for this curing appears to be as follows:

In the batch composing ordinary'sheet celluloid or other cellulose materials there are used, during the process of kneading, solvents such as alcohols, ethers, etc. which have relatively high vapor pressures-and low boiling points; these liquids act as free solvents; the object of the curing process is to remove the free solvents, but in common practice of commercial curingmore or less of the free solvents remain. At ordinary atmospheric temperatures, the amount of free solvent does not seem to cause let-goes, but when the temperature is raised, for example in automobile glass exposed to the-summer sun, these free solvents tend to find an outlet, and their increased vapor pressure pushes the adjacent laminations away and causes a separation in the sandwich.

It is an important feature of the present 5 process that the plastic material used is of cured before it can be satisfactorily used.

Referring to Fig. 1', the numeral 10 designates a container in which a plastic mass of material 11 can be made. Hlu'strated diasuch a nature that it does not have to be grammatically, and designated by the innmeral 12, is an agitating or stirring member which may be used to make the massll thor oughly homogeneous. Afterthe mass has been suitably mixed, and heat treated if desired, it is permitted to pass from said receptacle' between kneading and sizing rolls 13 which form a sheet or a gob 14 from said material. The sheet 14 may be conveyed on a suitable means 15 as will be readily understood.

In Fig. 2, respectively, are shown, and a sheet'18 of plastic material. as produced with the machine shown in Fig. 1, is interposed theretwo-sheets of glass 16 and 17, r I,

I 'i as sure of the mixture .is'reduced, by mutual between. Fig. 2, the sheet 18 is shown of substantially greater .thickness than the resultant film 19 shown in Fig. 4. Although itis not necessary, the process may be practiced by heating such a relatively thick intermediatemember and pressing the sheets of glass to reduce the intermediate sheet or gob to apredetermined' uniform thickness.

In some instances it may be desirable to make the gob sufiiciently large that it will extend 'past the edges of-the sheet as shown. In such.

cases-the excess is trimmed 'oli by a sharp, implement or the like.

Due to the mixture of the plastic material, the sheet 14 may be used immediately 1 after it has been formed without the neces+ of'batches that may be used, the following In the firstinixture, the triacetin is a high boilingpoint, low vapor pressure-solvent orplas ticizer, and due to its nature the plastic material formed by the mixture of cellulose acetate and triacetin can be used without curing.

One, object of this invention is to use a mixture of plasticizers. and solvents of such a character that the resulting vapor pressolution, to a relatively very low point, Or,- in other words, as is well'known in physical v chemistry, the addition of a solvent having a. l'o'w' vapor. pressure to a solvent having a high vapor-pressure-where the two" materials ness. Also, the plastic can either be united directly to the surface of the glass sheets or intermediate skins can be used. In such cases suitable skins are formed on the glass sheets, and the improved plastic united to the skins. Of course, the skins can be formed from plastic having the same general characteristics of the batches above given;

Any desired solvent, cements, etc. can, be used to. assist inobtaining a bond between the laminations, although their use is not imperative. It is to be understood that the form'of the invention herewith shown and/described is to be taken as the preferred embodiment of the same, and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit ofthe inventionor the scope of the j subjoined claims. 1

We claim-z 1 i i I A v 1. As a new article of manufacture, a sheet of laminated glass including a lamination ofuncured plastic material having a. low vapor' pressure.

2. As a new articleof-inanufacture, a sheet of laminated. glass including'a lamination of uncured cellulose material having alow vapor pressure. I A

3. As a new article of manufacture, a sheet of laminated glass including alamination ofuncured cellulose plastic composition having a high boiling point and a low vapor pressure. Signed at'Toledo, in the county ofLucas and State of Ohio, this 14th day of July,

' JOHN ana -ER. I

GEORGE B. WATKINS; WILBUR.F.'BROWN.

arem-utually soluble, causes'a decrease in-the vapor pressure of thematerial having the.

I high vapor pressure. In the-example cited above, the additionv of triacetin-decreases the "totalvapor pressureof the mixturecaused ,by the'presence'o-f'camphor which has a relatively high vapor pressure. ,Therefore,jEx-

' pressure solvent in the 55 to which laminated'glass is ordinarily sub-.- jected, have a vapor pressurelow enough so that let-goes willnot develop.

V ample (2) citedabo'v'e will, 'at temperatures, 50

By using a high boilin point, low vapor I atch, the finished product will .be suitable for use in-the manufacture of laminated glass because the temperatures to which the finished sheet are subjected will not causeany reaction. Another important part of the invention. is that, .al

though a high vapor pressure material is used, additional ingredients are used to cut 2 ,down the vapor pressure p oint.-

Of course, the-material does nothave to be used inf the form of a gob, as it can readily Iv 65 be formed into sheets of the required thick- 

